diff -r 3fcc279c921b -r d382dacfd73f rt/emul/compact/src/main/java/java/lang/ref/ReferenceQueue.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rt/emul/compact/src/main/java/java/lang/ref/ReferenceQueue.java	Tue Feb 26 16:54:16 2013 +0100
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 1997, 2005, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.lang.ref;
+
+/**
+ * Reference queues, to which registered reference objects are appended by the
+ * garbage collector after the appropriate reachability changes are detected.
+ *
+ * @author   Mark Reinhold
+ * @since    1.2
+ */
+
+public class ReferenceQueue<T> {
+
+    /**
+     * Constructs a new reference-object queue.
+     */
+    public ReferenceQueue() { }
+
+    private static class Null extends ReferenceQueue {
+        boolean enqueue(Reference r) {
+            return false;
+        }
+    }
+
+    static ReferenceQueue NULL = new Null();
+    static ReferenceQueue ENQUEUED = new Null();
+
+    static private class Lock { };
+    private Lock lock = new Lock();
+    private volatile Reference<? extends T> head = null;
+    private long queueLength = 0;
+
+    boolean enqueue(Reference<? extends T> r) { /* Called only by Reference class */
+        synchronized (r) {
+            if (r.queue == ENQUEUED) return false;
+            synchronized (lock) {
+                r.queue = ENQUEUED;
+                r.next = (head == null) ? r : head;
+                head = r;
+                queueLength++;
+                lock.notifyAll();
+                return true;
+            }
+        }
+    }
+
+    private Reference<? extends T> reallyPoll() {       /* Must hold lock */
+        if (head != null) {
+            Reference<? extends T> r = head;
+            head = (r.next == r) ? null : r.next;
+            r.queue = NULL;
+            r.next = r;
+            queueLength--;
+            return r;
+        }
+        return null;
+    }
+
+    /**
+     * Polls this queue to see if a reference object is available.  If one is
+     * available without further delay then it is removed from the queue and
+     * returned.  Otherwise this method immediately returns <tt>null</tt>.
+     *
+     * @return  A reference object, if one was immediately available,
+     *          otherwise <code>null</code>
+     */
+    public Reference<? extends T> poll() {
+        if (head == null)
+            return null;
+        synchronized (lock) {
+            return reallyPoll();
+        }
+    }
+
+    /**
+     * Removes the next reference object in this queue, blocking until either
+     * one becomes available or the given timeout period expires.
+     *
+     * <p> This method does not offer real-time guarantees: It schedules the
+     * timeout as if by invoking the {@link Object#wait(long)} method.
+     *
+     * @param  timeout  If positive, block for up to <code>timeout</code>
+     *                  milliseconds while waiting for a reference to be
+     *                  added to this queue.  If zero, block indefinitely.
+     *
+     * @return  A reference object, if one was available within the specified
+     *          timeout period, otherwise <code>null</code>
+     *
+     * @throws  IllegalArgumentException
+     *          If the value of the timeout argument is negative
+     *
+     * @throws  InterruptedException
+     *          If the timeout wait is interrupted
+     */
+    public Reference<? extends T> remove(long timeout)
+        throws IllegalArgumentException, InterruptedException
+    {
+        if (timeout < 0) {
+            throw new IllegalArgumentException("Negative timeout value");
+        }
+        synchronized (lock) {
+            Reference<? extends T> r = reallyPoll();
+            if (r != null) return r;
+            for (;;) {
+                lock.wait(timeout);
+                r = reallyPoll();
+                if (r != null) return r;
+                if (timeout != 0) return null;
+            }
+        }
+    }
+
+    /**
+     * Removes the next reference object in this queue, blocking until one
+     * becomes available.
+     *
+     * @return A reference object, blocking until one becomes available
+     * @throws  InterruptedException  If the wait is interrupted
+     */
+    public Reference<? extends T> remove() throws InterruptedException {
+        return remove(0);
+    }
+
+}